Copper(I)/NO_(g) Reductive Coupling Producing a <i>trans</i>-Hyponitrite Bridged Dicopper(II) Complex: Redox Reversal Giving Copper(I)/NO_(g) Disproportionation

A copper complex, [CuI(tmpa)­(MeCN)]+, effectively reductively couples NO(g) at RT in methanol (MeOH), giving a structurally characterized hyponitrito-dicopper­(II) adduct. Hydrogen-bonding from MeOH is critical for the hyponitrite complex formation and stabilization. This complex exhibits the reverse redox process in aprotic solvents, giving CuI + NO(g), leading to CuI-mediated NO(g)-disproportionation. The relationship of this chemistry to biological iron and/or copper mediated NO(g) reductive coupling to give N2O(g) is discussed.